This disclosure relates generally to the field of coiled tubing conveyance apparatus. More specifically, the disclosure relates to coiled tubing conveyance apparatus having a relatively small deployment area or “footprint” that may be used for purposes, among others, for shallow sediment evaluation below the bottom of a body of water.
Coiled tubing apparatus known in the art for use in wellbore construction and intervention operations include a reel on which a continuous length of flexible conduit or tubing is mounted. The reel may be transported to a wellbore location on a road vehicle such as a truck, or for marine wellbore operations on a skid which may be supported on a platform above the water surface. A device known as a “gooseneck” may be deployed on the same or on a different skid or vehicle. A gooseneck includes a plurality of rollers arranged on a curved frame to enable the flexible conduit to be redirected from a direction tangent to the reel to a direction generally vertical above a wellbore. A tubing injector is disposed above the wellbore and include traction rollers to move the tubing into the wellbore or out of the wellbore.
An example of such a coiled tubing unit known in the art is described in U.S. Pat. No. 6,719,043 issued to Austbo et al. FIG. 1. shows such coiled tubing apparatus, wherein the tubing injector is shown and generally designated by the numeral 10. The injector 10 is shown positioned above a wellhead 12 of a well 13 at a ground surface or subsea floor 14. A lubricator or stuffing box 16 is connected to the upper end of the wellhead 12. The tubing 18, having a longitudinal central axis 20 and an outer diameter or outer surface 22, is supplied on a large drum, or reel 24 and is typically several thousand feet in length. The tubing 18 of sufficient length, such as 10,000 feet or greater, may be inserted into the well 13 either as single tubing, or as tubing spliced by connectors or by welding. Outer diameters of the tubing 18 typically range from approximately one inch (2.5 cm) to approximately five inches (12.5 cm). The injector 10 is readily adaptable to even larger diameters. The tubing 18 is normally spooled from the reel 24 typically supported on a truck (not shown) for mobile operations. The injector 10 is mounted above the wellhead 12 on legs 26. A guide framework, that is, a gooseneck 28 having a plurality of pairs of guide rollers 30 and 32 rotatably mounted thereon extends upwardly from the injector 10. The tubing 18 is supplied from the reel 24 and is run between the rollers 30 and 32. As the tubing 18 is unspooled from the reel 24, generally it will pass adjacent to a measuring device, such as a wheel 34. Alternatively, the measuring device may be part of the injector 10, such as described in U.S. Pat. No. 5,234,053, issued to Connell.
The rollers 30 and 32 define a pathway for the tubing 18 so that the curvature in the tubing 18 is slowly straightened as it enters the injector 10. The tubing 18 is preferably formed of a material which is sufficiently flexible and ductile that it can be curved for storage on the reel 24 and also later straightened. The rollers 30 and 32 are spaced such that straightening of the tubing 18 is accomplished wherein the tubing 18 is inserted into the well 13 without kinks or undue bending on the tubing 18.
In some circumstances, for example, in a self contained coiled tubing apparatus to be deployed on a single vehicle or skid, or in environmentally sensitive areas, it may be desirable to minimize the area occupied by the coiled tubing apparatus.